Add a disabled property to DOMUI lists

chrome/browser/resources/options/options_page.css

Index: chrome/browser/resources/options/options_page.css
diff --git a/chrome/browser/resources/options/options_page.css b/chrome/browser/resources/options/options_page.css
index d5398afd2f988dcceff295a422b4374c869400f2..425ce811ba237cca9226d0bb85d02b90826215af 100644
--- a/chrome/browser/resources/options/options_page.css
+++ b/chrome/browser/resources/options/options_page.css
@@ -348,7 +348,7 @@ list > * {
   border: none;
 }
 
-list > :hover {
+list:not([disabled]) > :hover {
   background-color: #f2f2f2;
 }
 
@@ -357,9 +357,23 @@ list:focus > [selected],
 list:focus > [lead][selected],
 list > [selected]:hover {
   background-color: #f2f2f2;
+  background-image: none;
+}
+
+list > [lead][selected],
+list:focus > [lead][selected] {
   border-top: 1px solid #b2b2b2;
   border-bottom: 1px solid #b2b2b2;
-  background-image: none;
+  z-index: 3;
+}
+
+list[disabled] > [lead][selected],
+list[disabled]:focus > [lead][selected] {
+  border: none;
+}
+
+list[disabled] {
+  opacity: 0.6;
 }
 
 list > .heading {